Scotland goalkeeper Craig Gordon was the hero with two penalty saves as in-form Hearts fought back to reach the quarter-finals of the Scottish Gas Scottish Cup with a 4-2 shootout victory over St Mirren on a tense night at SMISA Stadium.

The Edinburgh side looked on course to exit the competition as they trailed to a first-half goal from Mikael Mandron until Australian midfielder Calem Nieuwenhof, who had not played since March 3 last year due to a hamstring problem, stepped off the bench in the 84th minute to equalise within seconds of entering the fray.

With the tie still deadlocked at 1-1 at the end of extra-time, Neil Critchley’s resurgent side – unbeaten since Boxing Day – then secured their progress in the shootout as 42-year-old goalkeeper Gordon saved the Buddies’ first two kicks from Oisin Smyth and James Scott.

James Penrice sealed the Jambos’ victory after Gerald Taylor had seen his kick – Hearts’ fourth – saved by Zach Hemming.

St Mirren boss Stephen Robinson changed his two wing-backs from the 1-0 defeat at St Johnstone as on-loan Kortrijk player Ryan Alebiosu came in for his debut in place of Elvis Bwonomo on the right and Declan John took over from Scott Tanser on the opposite side.

There was one change to the Hearts side that made it seven in a row undefeated with a 6-0 win at Dundee as Alan Forrest came in for his first start since December to replace Musa Drammeh. Norwegian midfielder Sander Kartum was named on the bench for the first time since his January arrival from SK Brann.

Saints, who had lost five of their previous seven matches, spurned a great chance in the fourth minute when Toyosi Olusanya lobbed the ball over the crossbar after getting in behind the Hearts defence to latch on to goalkeeper Hemming’s long kick-out.

The visitors’ first attempt came in the 13th minute when January signing Elton Kabangu – buoyed by five goals in his previous three outings – saw his ferocious low strike from 20 yards out pushed behind by Hemming.

Saints soon started to crank up the pressure, however, with Marcus Fraser having an effort blocked in the box by Beni Baningime before Hearts defender Jamie McCart had to make a vital interception to stop Mandron turning in a low delivery from Olusanya, who had latched on to a slack Adam Forrester passback and drawn Gordon out to the left edge of his six-yard box.

The Buddies broke the deadlock in the 22nd minute when Mandron reacted quickest to stab home the rebound from just inside the six-yard box after Mark O’Hara’s low curling shot from the angle of the area was parried out by Gordon.

Hearts offered little in response for the remainder of the first half and were booed off by their 1,600 travelling supporters at the break.

Things nearly got worse for the the visitors, with Olusanya and Killian Phillips both missing good chances early in the second half.

The Tynecastle side then lost Lewis Neilson and Cammy Devlin to injuries, with January signings Michael Steinwender and Kartum entering the fray to help salvage the tie.

But it was another substitute who eventually got Hearts on level terms in the 84th minute when Nieuwenhof was perfectly placed to drill home from 10 yards out after Penrice’s attempt to get a shot away from James Wilson’s low cross broke into his path off Phillips.

It proved a pivotal moment as the Jambos eventually prevailed at the end of a long and gruelling encounter.